Salted eggs were almost certainly created as a way to preserve an abundance of eggs to eat when times were leaner. The best ones are duck eggs, because they are larger and have a richer, more oily yolk than those from chickens.
It’s not difficult to make them – it just takes time. You put the uncooked whole eggs – shell and all – in a heavy saltwater brine in a tall jar or container, so the eggs have plenty of room to bob around.
The brine penetrates the porous shell, and as the egg gets heavier from the absorbed salt, it sinks to the bottom of the container.
I prefer to buy them, though – almost any shop that sells Asian ingredients will carry them. Salted eggs are often coated in a layer of ash, which needs to be scraped off before the eggs are cooked. In some Southeast Asian countries, salted eggs are dyed pink, to differentiate them from unsalted ones; and often, they are cooked. This recipe calls for uncooked salted eggs.
Salted egg yolk prawns is a popular Cantonese dish, but I’ve given it a Southeast Asian touch with the addition of curry leaves and fresh chillies – an idea I got from eating salted egg yolk crisps and fish skins. The curry leaves and fresh chilli are optional ingredients, but they add a lot of fragrance to the dish.
If the eggs are coated with ash, scrape it off with a knife, then rinse them thoroughly.
Put the eggs in a pan and add water to cover by about 2.5cm (1 in). Place the pan over a high flame and bring to a boil. Simmer for two minutes, then turn off the flame, cover the pan with the lid and leave for 10 minutes.
Drain the water from the pot then rinse the eggs. Leave them in cold water until they are cool enough to handle.
Remove and discard the egg shells and whites. Mash the egg yolks with a fork (or potato masher) until they are as smooth as possible.
Mix the egg yolks with the rice wine, salt, sugar and white pepper.
Prepare the prawns. Use kitchen shears to snip off the front of the head, cutting just behind the eyes. Trim off the antennae and legs. If the prawns have a sharp row of ridges on the top of the head, trim it to smooth it out.
Use the kitchen shears to slice open the shell along the back, cutting from the base of the tail to the head. Make a slit in the back flesh to expose the vein, then pull it out and discard it.
Cut the stalks of curry leaves into shorter lengths. Slice the chillies into thin rings, shaking out and discarding the seeds as you go. Slice the spring onion lengthwise into fine shreds, then cut the shreds into 2.5cm (1 in) lengths.
Pour oil to a depth of about 9cm (3½ in) in a wok and heat to 180° C (350° F).
While the oil is heating, coat the prawns lightly but thoroughly with the potato or corn starch, then shake off the excess. Fry the prawns a few at a time, just until they curl and turn pink – do not overcook. Remove them from the hot oil and drain on paper towels.
After cooking all the prawns, add the curry leaves and fry them just until they darken slightly. Drain on paper towels.
Pour the oil from the wok. Wash the wok, then dry it.
Place the wok over a medium flame and when it’s hot, add the butter. When the butter is about three-quarters melted, stir in the chilli pieces, then add the egg yolk mixture. Stir well so the butter and egg yolks are thoroughly combined. Taste the ingredients and adjust the seasonings, if necessary – it might need a little more salt.
When the ingredients are bubbling in the wok, add the prawns and curry leaves. Stir constantly for a few minutes, or until the egg yolk mixture coats the prawns.
Transfer the ingredients to a dish, garnish with spring onion and serve.